Page:Graphic methods for presenting facts (1914).djvu/286

 *zontal arrangement is useful for another purpose. By having loose cards, we can arrange the cards either horizontally or vertically and get all the advantages of either position. Curves plotted in loose-leaf books, or on large sheets of paper, cannot have this flexibility of arrangement, and they accordingly handicap the executive in the analysis of data which may be vital to the success of his business.

When the cards are arranged horizontally the figures for the curve over a series of years are in plain sight, while in the vertical arrangement one card hides the figures on another card. Figures are essential to the true interpretation of curves like those seen in Fig. 208. In looking at Fig. 208 most readers are likely to feel that the business of the year 1911 was much better than the business of the year 1910. When we look at the total figures, however, we see that the sales for the year 1911 were only $1,435,041, while the sales for 1910 were $1,575,298. Not only were the total sales for 1911 much less than the sales for 1910, but there was a very great fluctuation in sales from month to month which created a very difficult problem in the operation of the manufacturing plant. In the early half of the fiscal year ending in 1911, men were not needed because of the small volume of sales, and a large portion of the working force had to be discharged. In the latter half of the fiscal year, sales increased so rapidly that men had to be hired in large numbers. Inevitably, therefore, many unskilled men were obtained who were sure to spoil a large volume of any output requiring the great accuracy needed by automobile parts. The record for the fiscal year ending 1911 was in every way bad, as compared with that for the fiscal year 1910. The company eventually ended in a receivership.

Cards only four inches by six are of sufficient height to hold the co-ordinate ruling needed for curve plotting, and yet have room above the ruled field for two separate columns of figures of seven digits each, as well as space across the top for a title which may run the whole length of the card. In Fig. 208 we have two sets of figures, one set for months and the other set for quarters. Each set of figures contains six numerals. Although the illustration in Fig. 208 is only about one half the natural size of the card, the figures themselves are clearly legible and the title at the top of the card is easily read.

One of the chief advantages in the use of loose cards lies in the fact that any set of cards may be laid out on a table and compared with any other set of cards in the manner shown in Fig. 209. It is